188 Animal Intelligence 
abundant opportunity to realize that one signal meant 
food at the bottom of the cage and another none, a monkey 
would not act from the obvious inference and consistently 
stay up or go down as the case might be, but would make 
errors such as would be natural if he acted under the growing 
influence of an association between sense-impression and 
impulse or sense-impression and idea, but quite incompre- 
hensible if he had compared the two signals and made a 
definite inference.| We shall find that, after experience 
ith several pairs of signals, the monkeys yet failed, when 
a new pair was used, to do the obvious thing to a rational 
mind; viz., to compare the two, think which meant food, 
and act on the knowledge directly. 
The methods one has to take to get them to do anything, 
their general conduct in becoming tame and in the ex- 
periments throughout, confirm these conclusions. The 
following particular phenomena are samples of the many 
which are inconsistent with the presence of reasoning as 
a general function. No. 1 had learned to open a door by 
pushing a bar around from a ‘horizontal to a vertical posi- 
tion. The same box was then fitted with two bars. He 
turned the first bar round thirteen times before attempting 
to push the other bar around. In box LL all three monkeys 
would in the early trials do one or two of the acts over and 
over after they had once done them. No. 1, who had 
learned to pull a loop of wire off from a nail, failed thereafter 
to pull off a similar loop made of string. No. 1 and No. 3 
had learned to poke their left hands through the cage for 
me to take and operate a chute with. It was extremely 
difficult to get either of them to put his right hand through 
or even to let me take it and pull it through. 
A negative answer to the question “Do the monkeys 
reason?” thus seems inevitable, but I do not attach to 
